Headset gives a voice to the voice box-less

2019-03-07 05:18:21

By Helen Knight People who have lost their larynx to cancer could speak again, thanks to a device that can interpret facial movements when the wearer mouths a word IMAGINE you open your mouth to speak but not a single word emerges. This is the distressing and frustrating situation faced by people who have had their larynx removed following cancer, disease or injury. To help them communicate they are often fitted with a valve in their throat to divert air from the lungs to the oesophagus when they exhale, generating a form of speech. But these valves tend to become clogged after only a few months and need to be replaced. So a team in the UK is developing a device that can detect and interpret facial movements when someone mouths a word, recognising what they are saying. “We can pick up information about the way they are moving their lips, teeth and tongue around, and from that information reconstruct their speech,” says team member Phil Green at the University of Sheffield. The device uses small magnets placed inside the mouth and on the tongue to create a magnetic field. Changes in the field as the person mouths a word are detected by sensors attached to an external headset (pictured above). The system is trained to recognise the patterns of positional changes that correspond to the individual wearer mouthing particular words. So far, the system can recognise about 50 words, says Green. The team plans to develop magnets that can be safely implanted into the tongue, says team leader James Gilbert at the University of Hull. The researchers are also aiming to reduce the size of the headset that holds the sensors down to that of a Bluetooth device. Still, it will be a challenge to arrange the magnets in such a way that they produce enough information to recognise what the wearer is saying without causing them discomfort, says Patrick Naylor, an expert in speech recognition and enhancement at Imperial College London. While losing your speech entirely is thankfully relatively rare, thousands of people each year who suffer a stroke – or those with cerebral palsy, Parkinson’s disease or motor neurone disease – can lose the ability to speak coherently. Just as human listeners have trouble understanding impaired speech, so do conventional speech-recognition systems, says Stuart Cunningham, also at the University of Sheffield. He and his colleagues are developing an iPad-sized prototype that could learn to recognise impaired speech and replay a clearer version. This system is trained on a number of recordings of the person’s voice so that it learns to recognise their individual speech patterns. Once the system has recognised a word, it is replayed by a voice synthesiser. Alternatively, a few minutes of voice recording is taken from a family member – or the person themselves, if made before their impairment becomes too severe- and used to adapt a standard artificial voice. Devices that can clarify impaired speech are far quicker than relying on typed text, says Cunningham. His team’s prototype was developed in collaboration with the National Health Service, communication device maker Toby Churchill and speech-recognition specialist El Pedium Technologies, all in the UK. They plan to begin testing on people in the next 12 months. AN ANIMATED talking avatar could help people learn a foreign language. The avatar, named Tara, is designed to show people learning another language the precise mouth movements that should be made to generate a given word. As well as an external view of Tara’s speaking head, the system also displays the internal workings of her mouth and tongue as the word is spoken, says its developer Priya Dey, at the University of Sheffield, UK. These were generated from magnetic resonance images taken of Dey’s own head and neck as she was speaking. In a small pilot trial of five native Arabic speakers learning English,